Men account for 29% of fractures and 25% of fracture-related costs in the US. Although fewer fractures occur in men compared to women, men are of special interest because they are more likely to die within 1 year after a hip fracture. Bone mineral density (BMD) testing to identify and treat osteoporosis (very low BMD) has been proposed as a method to prevent disabling fractures in older men, largely because this is an accepted screening strategy in women aged 65 years and older. However, the efficacy of BMD screening in men is uncertain. Because an RCT of osteoporosis screening is not considered feasible, observational studies are needed to test how BMD screening should be used for identification of older men at high risk of fracture, and to assess whether death from other (non-fracture-related) causes overwhelms the risk of incident hip or clinical vertebral fracture in the oldest old of men. Risk factor assessment should also be studied because clinical practice guidelines recommend risk assessment to guide the selection of men for BMD screening. Our long-term goal is to identify a high-risk group of older men that should have routine BMD screening and risk factor assessment to select candidates for medications to reduce major fractures. We hypothesize that in men aged 65 and older, the relative incidence of first hip or clinical vertebral fracture vs. incidence of other-cause death will peak within an optimal age range when BMD screening could be considered, with subsequent decreasing benefit from BMD screening with increasing age. We further hypothesize that clinical risk factors will predict incident hip or clinical vertebral fracture as accurately as BMD in older men. Our planned analyses of data from the Osteoporotic Fractures in Men Study (MrOS) will inform a selective BMD screening strategy for a high-risk group of older men, accommodating men's clinical risk factors for fracture and increasingly higher rate of other-cause death with advancing age. Specific aims of this project: 1) Compare the time to first hip or clinical vertebral fracture vs. ime to other-cause death according to age group in older men; 2) Compare the time to first hip or clinical vertebral fracture in older men with lower vs. higher baseline BMD T-scores; 3) Estimate the accuracy of fracture risk assessment scores without and with BMD to predict hip or major osteoporotic fracture in older men. Impact: Successful completion of these aims will demonstrate that BMD screening in a high-risk group of older men will predict significant numbers of major fracture cases, and will test whether risk factor assessment is a strong adjunct to BMD screening in men. These findings would provide a stronger evidence base for men's fracture prevention guidelines than those currently based on expert opinion.